Ball joint

ABSTRACT

A ball member is turnably accommodated in a socket and a pressure-exerting element is threaded into the socket and can be turned in a sense advancing its leading end towards the surface of the ball member. A deformable insert member is located between the ball member and the leading end of the pressure-exerting member and the surface area of contact between it and the leading end of the pressure-exerting member is smaller than the surface area of contact between it and the ball member whereby forces exerted upon the pressure-transmitting member by the pressureexerting member are amplified when they are transmitted to the ball member.

United States Patent [451 July 11, 1972 Glatz BALL JOINT [72] Inventor:Albert Glatz, Teuchelwiesstrasse l3, Frauenfeld, Switzerland [22] Filed:Oct. 5, 1970 [21] Appl. No.: 78,034

[30] Foreign Application Priority Data Oct. 6, 1969 Switzerland..l5027/69 [52] US. Cl ..287/l2, 287/87 [51] Int. Cl. ..Fl6c 11/06 [58]FieldofSearch ..287/l2,2l,87

[56] References Cited UNITED STATES PATENTS 2,736,580 2/1956 Boetcker287/l2 3,240,516 3/1966 Barish et al ....287/l2 2,670,228 2/1954Pagliuso ....287/87 654,051 7/1900 Brown et a] ..287/12 FOREIGN PATENTSOR APPLICATIONS 449,488 6/1936 GreatBritain ..287/2l 440,670 l/l936GreatBritain ..287/l2 Primary Examiner-Andrew V. KundratAttorney-Michael S. Striker ABSTRACT A ball member is tumablyaccommodated in a socket and a pressure-exerting element is threadedinto the socket and can be turned in a sense advancing its leading endtowards the surface of the ball member. A deformable insert member islocated between the ball member and the leading end of thepressure-exerting member and the surface area of contact between it andthe leading end of the pressure-exerting member is smaller than thesurface area of contact between it and the ball member whereby forcesexerted upon the pressure-transmitting member by the pressure-exertingmember are amplified when they are transmitted to the ball member,

10 Claims, 1 Drawing Figure BALL JOINT The present invention relatesgenerally to ball joints, and more particularly to ball joints which canbe selectively arrested against movement.

It is frequently necessary to arrest a ball joint against movement inorder to maintain it in a selected position. This of course has longbeen recognized in the art and there are many constructions of balljoints available which can be so arrested. One approach to the problemis to use clamping screws or setting screws which are threaded into thesocket of the joint and whose leading end engages the surface of theball member. The pressure exerted upon the ball member with such screwsis, however, too small in order to prevent the ball member from turningif substantial forces act upon it in a sense tending to turn it;alternately, the force required for effecting the blocking is so greatthat it cannot be provided in a convenient manner, that is by providingthe setting screw with a handwheel of reasonable size. Of course it isconceivable to make the handwheel very large in such cases, but spacerequirements very rarely permit such an approach.

An attempt to avoid these difficulties is found in the type of balljoint which is blocked by means of oil-hydraulic clamping devices. Thesecan be constructed in various different ways, for instance in form ofpressure cylinders of different diameters which amplify the pressureforce exerted and transmitted to the ball member. They also, however,have a disadvantage, namely the fact that they are difficult to sealagainst escape of oil and therefore are rather expensive to construct.If despite the expensive sealing necessary even very small quantities ofoil manage to leak, the blocking force exerted is reduced and it istherefore not possible to reliably expect freedom of such constructionsfrom malfunction, which in turn of course adversely affects their safetyof operation.

SUMMARY OF THE INVENTION It is, accordingly, an object of the presentinvention to overcome the aforementioned disadvantages.

More particularly, it is an object of the invention to provide a balljoint construction wherein the ball member can be blocked as required,and which is not possessed of the aforementioned disadvantages.

A concomitant object of the invention is to provide such a ball jointconstruction which is very simple and therefore inexpensive, but whichfor this reason is also resistant to malfunction and highly reliable inits operation.

In pursuance of the above objects, and others which will become apparenthereafter, one feature of the invention resides in a ball joint which,briefly stated, comprises a socket and a ball member turnablyaccommodated in the socket. First means is operable for exerting ablocking force so as to prevent turning of the ball member when desired,and second means cooperates with the first means and with the ballmember and is operative for amplifying the force exerted by the formerand for transmitting it in amplified condition to the latter.

The second means comprises, according to the present invention, anelastically or plastically deformable member which is so arranged thatthe area of contact between one of its sides and the force-exertingfirst means is smaller than the area of contact between its other sideand the ball member, it being understood that the contact in either casemay be direct or indirect.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation, together with additional objects and advantages thereof, willbe best understood from the following description of specificembodiments when read in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING The single FIGURE is a somewhatdiagrammatic partially longitudinally sectioned view showing oneembodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Discussing now the drawing indetail, it will be seen that the joint in toto is identified withreference numeral 1. It has a housing of socket composed of the uppersection 1' and the lower section 1" which extends into the upper section1'. The lower section 1" has an edge portion 2 remote from the uppersection 1' which is deformed inwardly of the hollow lower section 1", asparticularly clearly shown in the sectioned part of the FIGURE, in orderto prevent the ball member 3 which is accommodated in the lower section1" from falling out through the open end of the lower section 1Accommodated in the interior of the housing is a substantiallyfunnel-shaped cup 4 having a cylindrical end portion 5 remote from theball member 3, this portion 5 being guided in a cylindrical bore oraperture 6 of the upper section 1'. As the drawing clearly shows, theball member 3 is partially accommodated in the open end of thefunnel-shaped cup 4.

Pins, screws, bolts or the like are identified with reference numeral 7and are provided in the lower section 1 of the housing, projectinginwardly therein and engaging in grooves 8 extending axially of the cup4, in order to prevent the latter from turning movement within thehousing.

A threaded stem 14 is in mesh with the internal threads of tapped bore10 provided in the upper section 1; it is fast within non-illustratedself-evident manner-a handgrip, handwheel, or the like identified withreference numeral 9. Thus, the turning of the handwheel 9 effectsturning of the threaded stem 14 in a sense either moving the same deeperinto or withdrawing it from the tapped bore 10, depending upon thedirection in which the handgrip 9 is rotated. Of course, when it hasbeen said before that the manner in which the handgrip or handwheel 9 isfast with the stem 14 is selfevident, then it will be appreciated thatany suitable means may be provided for this purpose, all such meansbeing well known in the art and including, for instance, the possibilitythat the stem 14 may be of one piece with the handwheel 9.

In any case, it will be appreciated that if the leading end of the stem14 were to bear directly upon the cup 4 which in turn then would beforced into frictional engagement with the surface of the ball member 3,the pressure to be obtained in this manner would be too small toguarantee a blocking of the ball member against movement relative to thesocket if any substantial forces were to act upon the ball joint in asense tending to effect relative displacement of the ball member andsocket. The alternative, to make the handwheel 9 substantially larger inorder to obtain the necessary force but with the exertion of only normalstrength, is usually out of the question because of lack of availablespace and for various other reasons, including the fact that thehandwheel 9 would then have to be disproportionally larger with respectto the remainder of the oint.

The invention solves this problem by amplifying the force exerted by thehandwheel 9 via the threaded stem 14, before it is transmitted to theball member 3. Accordingly, this invention provides a bore 11 in thecylindrical portion 5 of the cup 4, with the bore having a substantiallylarger diameter than a pin 12 which is accommodated in the bore. The endof the bore 11 which is directed towards the ball member 3 is closed bya plate portion 13. The pin 12 is shorter than the bore 11 and guidedtherein by a ring 15. Located between the pin 12 and the plate 13 is anintermediate member 16 which is elastically or plastically deformableand which may consist for instance of natural or synthetic rubber, or asynthetic plastic material, as ethylene vinyl acetates, polyvinylchlorides or the like. It is this member 16 which acts as a forceamplifier.

When the handwheel 9 is turned in a sense causing the threaded stem 14to exert pressure upon the pin 12 which in turn exerts pressure with itsleading end upon the member 16, then the pressure exerted is transmittedinto tn member 16 only over a surface area corresponding to the area ofcontact between the member 16 and the leading end of the pin 12. Becauseof its deforrnability characteristics, the member 16 tends to transmitthis pressure in all directions but is prevented from doing so-that isfrom yielding-in those areas where it is bounded by various wallsurfaces, that is upwardly by the guide ring and latterly by the wall ofthe bore 11. Therefore, the entire force exerted upon the member 16 bythe pin 12 is transmitted to the plate 13 and is thus amplified, in thatthe force acting upon the plate 13 is larger than the force which istransmitted to the member 16 from the pin 12 by the same factor by whichthe surface area of contact between the member 16 and the plate portion13 is greater than the surface area of contact between the member 16 andthe leading end of the pin 12. In other words, the amplificationcorresponds to the square of the difference of the two interfacesbetween the member 16 and the plate portion 13 on the one hand, and themember 16 and the leading end of the pin 12 on the other hand. Thisevidently makes it possible to exert with the relatively small handwheel9 an adequate force which serves for blocking the ball member 3 even ifsubstantial forces act upon the latter in a sense tending to displace itwith reference to the housing.

It is an important advantage of the construction according to thepresent invention that the force amplification ratio can be very readilyand very simply modified by replacing the ring 15 and the pin 12, itbeing understood that the amplification ratio decreases as the surfacearea of the leading endface of the pin 12 increases, and vice versa.

Naturally the illustrated embodiment is only exemplary and variouspossible modifications will readily offer themselves to those skilled inthe art and are of course intended to be included within the scope andconcept of the invention. It is thus possible, for instance, to omit theplate portion 13 and instead have it replaced with a corresponding wallportion which is of one piece with the cup 4. in this case, the pressureexerted by the member 16 acts directly upon the cup 4 instead of via theintermediary of the plate portion 13. Another possibility modificationis a modification is to omit the plate portion 13 and to have the member16 contact the outer surface of the ball member 3 directly. If that isthe case, it is advantageous but not necessary that the surface of themember 16 which contacts the surface of the ball member 3 be conformedat least substantially to the contour of the surface of the ball member3, namely that it be of arcuately concave configurationi.e.,calotte-shaped or hemispherically-shapedhaving a radius of curvaturewhich corresponds to or at least resembles that of the ball member 3.

Naturally, various different materials are suitable for the variouscomponents and all such materials are intended to be included within theconcept and scope of the present invention.

It will be understood that each of the elements described above, or toor more together, may also find a useful application in other types ofconstructions differing from the types described above.

While the invention has been illustrated and described as embodied in aball joint, it is not intended to be limited to the details shown, sincevarious modifications and structural changes may be made withoutdeparting in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can by applying current knowledgereadily adapt it for various applications without omitting featuresthat, from the standpoint of prior art, fairly constitute essentialcharacteristics of the generic or specific aspects of this inventionand, therefore, such adaptations should and are intended to becomprehended within the meaning and range of equivalence of thefollowing claims.

What is claimed as new and desired to be protected by Letters Patent isset forth in the appended claims:

1. A ball joint, comprisinga socket having an outer cup por tionprovided with an open end, and an inner cup portion open toward saidopen end, said inner cup portion being located within said outer cupportion with limited freedom of axial movement toward and away from saidopen end; a ball member turnably accommodated in said open end andpartly located within said inner cup portion in at least line-contacttherewith; first means operable for exerting a thrust force toward saidball member so as to prevent turning of said ball member when desired;second means cooperating with said first means and said ball member andoperative for amplifying the force exerted by the former andtransmitting it in amplified condition to the latter via axial movementof said inner cup portion; and detent means cooperating with said innerand outer cup portions for preventing relative rotational movements ofthe same.

2. A ball joint as defined in claim 1, said first means having aforce-transmitting first surface of a first surface area acting uponsaid second means, and said second means having a force-transmittingsecond surface acting upon said ball member and having a larger secondsurface area.

3. A ball joint as defined in claim 2, said second means comprising anelement of deformable material; and said inner cup portion comprisingwall means surrounding said element and preventing deformation of thesame in a sense other than transmitting force to said ball member.

4. A ball joint as defined in claim 3, said wall means comprising anannular member surrounding said element, and a chamber-defining wallsurrounding and guiding said annular member. I

5. A ball joint as defined in claim 3; further comprising anintermediate pressure-transmitting member interposed between saidelement and said ball member and transmitting pressure from the formerto the latter.

6. A ball joint as defined in claim 2, said first means comprisingforce-exerting means, and transmitting means between the same and saidsecond means for transmitting force to the latter.

7. A ball joint as defined in claim 1, said second means transmittingforce to said inner cup portion in a sense efiecting pressure engagementof the latter with said ball member so as to transmit said forceindirectly to the latter.

8. A ball joint as defined in claim 7; and further comprising a platemember interposed between said second means and said inner cup portionand transmitting said force from the former to said inner cup portion.

9. A ball joint as defined in claim 7, said inner cup portion having aclosed side provided with a tubular extension open in directionoppositely away from said open end, and said second means being locatedin said extension with said first means extending into the same andcontacting said second means.

10. A ball joint as defined in claim 2, said inner cup portion having acontact surface contacting said ball member and being arcuately concaveon a radius which at least approximates the radius of curvature of saidball member.

1. A ball joint, comprising a socket having an outer cup portionprovided with an open end, and an inner cup portion open toward saidopen end, said inner cup portion being located within said outer cupportion with limited freedom of axial movement toward and away from saidopen end; a ball member turnably accommodated in said open end andpartly located within said inner cup portion in at least line-contacttherewith; first means operable for exerting a thrust force toward saidball member so as to prevent turning of said ball member when desired;second means cooperating with said first means and said ball member andoperative for amplifying the force exerted by the former andtransmitting it in amplified condition to the latter via axial movementof said inner cup portion; and detent means cooperating with said innerand outer cup portions for preventing relative rotational movements ofthe same.
 2. A ball joint as defined in claim 1, said first means havinga force-transmitting first surface of a first surface area acting uponsaid second means, and said second means having a force-transmittingsecond surface acting upon said ball member and having a larger secondsurface area.
 3. A ball joint as defined in claim 2, said second meanscomprising an element of deformable material; and said inner cup portioncomprising wall means surrounding said element and preventingdeformation of the same in a sense other than transmitting force to saidball member.
 4. A ball joint as defined in claim 3, said wall meanscomprising an annular member surrounding said element, and achamber-defining wall surrounding and guiding said annular member.
 5. Aball joint as defined in claim 3; further comprising an intermediatepressure-transmitting member interposed between said element and saidball member and transmitting pressure from the former to the latter. 6.A ball joint as defined in claim 2, said first means comprisingforce-exerting means, and transmitting means between the same and saidsecond means for transmitting force to the latter.
 7. A ball joint asdefined in claim 1, said second means transmitting force to said innercup portion in a sense effecting pressure engagement of the latter withsaid ball member so as to transmit said force indirectly to the latter.8. A ball joint as defined in claim 7; and further comprising a platemember interposed between said second means and said inner cup portionand transmitting said force from the former to said inner cup portion.9. A ball joint as defiNed in claim 7, said inner cup portion having aclosed side provided with a tubular extension open in directionoppositely away from said open end, and said second means being locatedin said extension with said first means extending into the same andcontacting said second means.
 10. A ball joint as defined in claim 2,said inner cup portion having a contact surface contacting said ballmember and being arcuately concave on a radius which at leastapproximates the radius of curvature of said ball member.